On the cover of this month’s issue of Systematic Biology is an article by Keith Barker, John Klicka, Scott Lanyon, Irby Lovette, and myself on the radiation of New World nine-primaries oscine birds. This group of birds is huge, containing about 8% of all bird species. About half of the birds are tanagers, birds that we have been studying in the Burns lab for years. The other birds in the group are familiar to North American birders and include blackbirds, sparrows, warblers, grosbeaks, and cardinals. The paper represents our first comprehensive look at the phylogeny of these birds, which we have been working on collectively for over 10 years. One of the more interesting findings is that the rate of speciation in tanagers has been significantly higher than that of other groups, with a rate of diversification similar to that of Hawaiian silverswords.  Taxonomically, we suggest some major changes at the family level. To preserve the 5 existing, familiar families, we had to add 11 other families. For example, the Yellow-breasted Chat now has its own family as well as some radiations unique to islands in the Caribbean. The cover looks pretty cool, with 13 of the 16 families represented by a photo. If you like this paper, stay tuned as we have several more in the works!

We recently published a paper in Molecular Phylogenetics and Evolution on plumage evolution in one of the many clades of tanagers. This paper represents a side project of Allison Shultz’s thesis. In the paper, we describe a novel clade of tanagers that includes Hemispingus, Poospiza, Thlypopsis, and nine other genera. A variety of species are included in the group, some of which were traditionally considering tanagers and some of which were traditionally considered finches. Among the species in the group is the Pardusco, Nephelornis oneilli. The clade is illustrative of the taxonomic mess of tanagers as many of these genera are not monophyletic in our analyses. In addition to describing relationships of these species, the paper also looks at how light environment shaped plumage evolution in the group. We found that evolution of brightness follows expectations for selection based on crypsis and that more colorful plumage is found in closed in environments than in open environments. For a pdf, you can go to journal’s web site or just send an e-mail to kburns@mail.sdsu.edu. If you like this paper, there will be more to come as Allison is currently writing up her thesis papers on plumage evolution in all 370 birds that we now consider to be tanagers.

Of four models of plumage evolution, one including open vs. closed habitats (highlighted in red) is preferred over the others. Species names on the left are color-coded by genera to illustrate widespread paraphyly within this clade of tanagers.

Together with co-authors at Harvard University, we recently published a paper in Proceedings of the National Academy of Sciences that described the evolution of beak developmental pathways in Darwin’s Fiches and their relatives. The paper includes three components: 1) a mathematical analyses of beak shape among the all species in the Tholospiza clade, 2) studies of beak development of Caribbean bullfinches in the genus Loxigilla, and 3) a new phylogeny of Darwin’s Finch relatives based on multiple genes. One of our more interesting findings is that species of Caribbean bullfinches have convergently evolved the exact same beak shape. Unexpectedly, this shape is controlled by different developmental pathways.

Here are links to a couple articles that describe our paper: Science Daily & Harvard Gazette

We just had a new paper published in The Auk, representing a collaboration between Burns and recent graduate student Allison Shultz. In this study, we used a spectrometer to quantify plumage in the cardinals and tanagers, which together make up the largest radiation of Neotropical songbirds. We found that almost half of the species have ultraviolet coloration in their plumage. This is coloration that birds can see, but humans and other mammals are unable to detect. Also, 97% of the birds appear sexually dichromatic to birds even though only about half look sexually dichromatic to humans. Therefore, we found many examples of species where males and females look different to birds, but seem identical to humans. Our paper was picked by the editor of The Auk as an Editor’s Choice.

The Paradise Tanager (Tangara chilensis) is one of the most colorful tanagers. Is this a male or female? Humans can’t tell, but birds can.